Method of producing concrete structures



Dec. 18, 1934. HAYDEN 1,985,092

METHOD OF PRODUCING CONCRETE STRUCTURES Filed March 5 1929 Arronwgy IPatented Dec. 18, 1934 f ra, a

, Application March 5, 1929, Serial No. 344,597 10mm. (Cris-4ntfo'concrete structures of the type which are produce'd by'the pouringof concrete into forms."

5 :Heretofore for the production of concrete structures such forexample, as are produced by pouring concrete into forms, the forms beingremoved after the concrete has set or'reached a condition of requiredrigidity, substantial difli culty has been met within efiectingproperycuring of the; concrete and the structures produced have beensubjected to internal stresses and strains due to changes in themoisture content of the structure. Changes in'temperature also result inthe development of certain types of stresses in concrete structures dueto the expansionor contraction of an element the structure resultingfrom such change in temperature. Allowance tor the anticipated variationof dimensionsdue to temperature changesis made in the design of thestructure; usually by the provision of expansion joints 'andvariations'in the dimensions of conturesdue to changes in the moisture e'lfstm .qn s e eo ma etsk ca of r y- Hqwever, in concrete structures;and more par ticularly where; for example, the concrete structure isreinforced with steel or the like," internal stresses develop withinthest'ructure as a result of change in iirnensions oi the structureresultin rram'vanatmns inthe moisture content thereof and which'cannotbe taken care of, as'can change indimerisi onsassuch, I I Heretof ore'the purines: concrete forming structures of the character produced bythe pour- 11 g of concrete intoiorms has been more or less deduatelyaccomplished by permitting theforms to remain on the-structurethroughout thedura- ,tion of thestipuIatedcuring period, or at leastuntil the structure *is isufliciently rigid-to permit the 'rmevar of theforms. However, where wooden forms are used, even though permitted tore'main in place 'until'fthe"-'concrete is cured, muchor the waternecessary-to complete the hydrationofthe Portland "cement is lost byevaporation through the porous form "wall unless theforms"'are"ireduentlvwetted:during the curing period and incases wherethe forms are removed pri'orto the-end of the stipulated curing period,ithas been necessary'to frequently wet the-exposed 'suriace or thestructure in an effort to 'inai'ntain-a'suflicient amount of water inthe con- The; Barber Asphalt Company,

corporation of West Virginia v J assignor to Philadelphia,

structures I pouring of concrete intoforms which have increased strengthand which" will be I free from the internal stresses incident tovariations in the moisture content thereof throughout the "life of thestructure, by ithe' encasement of thestructure in a waterimpervioussyste at-the time of pouring the concrete, into "the; form. YIt' I apparentthatitis unnecessary to makeprovi sion for dimensionalchanges" in the concrete. structure due to changes in'the moisturecontent thereof in structures so encased, as such dimensional changeswill be obviated.

Now, it is'the object of my invention to provide a method of producingconcrete structures, such as are produced by the pouring of concreteinto forms, by which themixing water will be conserved within thestructure for the complete hydration of the cement and themoisturecontent of the structure after the completion of such hydration will bepermanently stabilized: with the result that a structure ofmaximumstrength of the character produced by the will be templatesprovision-for the retention of the film on the concrete structure onremoval of the forms, the film as originally applied, or asit'may besupplemented, acting,after removal' of the forms, to maintain themoisture contentof the concrete at a substantially 'constant percentageregardless of variations atmospheric. conditions or other conditionswhich would tend to infiuence the moisture contentzthereof. f

Inthe adaptation" of the method in accordance with my invention topractice from the broad standpoint, Iprovidetheior'ms, into which theconcrete is to he poured, with a coating of a material capable ofsupporting'the water impervious film to be applied to the concrete. Thecoating serves'to support thefilm of water impervious material duringthe pouring of the concrete into the forms and is of such a characterthat after the concrete has been; poured and desirably puddled, theadherence-of the film to the concrete will be greater than its adherenceto the coating material, or than the adherencegof the coating materialto the forms, with c the result that on removal of the forms the waterimpervious film will remain adhered to the concrete. After removal ofthe forms any coating material adhering to the film is removed and ifdesired the film may be supplemented.

It will be understood that from the broad standpoint my inventioncontemplates the application of a water impervious "film to concrete asit is poured into forms and the retention of the film by the concreteafter the forms are removed, the application of the film being effectedthrough the medium of a film supporting coating initially applied to theforms. a

In carrying the method in accordance with my invention into practice,any type of forms for the formation of concrete structures may be used.However, the carrying out of the method will be facilitated where formsof the type which comprise sections composed of back and sides built inplace and having a-separable front section adapted to; be secured.inplace when the concrete is to be poured-are used. As an illustrationof the practicaladaptation of the method inaccordance with my inventionin, for example, the construction of a. wall,the forms, for example, ofthe typehav r g b ck and sides .built in place anda .remova-blefront,having been constructed, the interior; of the forms,-; including the.separable front section if the form is of such type,

are coated with a' coating of, for example, clay slurry, whitewash, orthe like,, the application being made, for example, by, brushing or by aspray gun, and there is formed upon the coating a waterimpervious film,for example, formed of a linseed oil paint, rubber latex, bitumen orbituminous material as, for example; asphalt, or of coal tar-pitch, orthe'like. The water impervious film may be formed upon the .coating,

' c. for example,-by brushing or spraying upon the coating a waterexternal phase bituminous emulsion, .heatedasphaltum, or asphaltumdissolved or cut back: by means of a suitable solvent. Where thewaterimpervious film is formed through the use of heated asphalt, orasphalt solution, the clay slurry.- coating should be permitted to drybefore application of the film forming material. However, where the filmis formed by the use of a bituminous emulsion, drying of the clay slurrycoating is not necessary prior to application of the film.

After the-formation of the water impervious film, as described above,the concrete is poured into the form and the surface thereof, at theopen top of the form, coated directly with a material which will form'awater impervious film, for example, amaterial similar tothat used informing the waterimpervious film on the coated forms as, for example, abituminous emulsion or an :asphalt solution, heated asphalt, coal tarpitch, or the like. The concrete is then permitted to set and when ithas set or hardened sufiiciently, the forms are removed. On removal ofthe'forms the water impervious film will remain adhered to the,concrete, since the adherence of the film to'the concrete, as will behereinafter described, may be made greater than to the clay coating; inany event the adherence of the water impervious film to the concretewill be greater than the adherence of the claycoating to the forms sothat on removal of the forms the film will remain with theconcretestructure formed. If desired, and'more'especially where the waterimpervious filmis formed with heated asphalt or asphalt solution,theadherence of the film to the concrete may be insured by the additionto the film after its formation and before it has set of a sharp mineralaggregate, as relatively finely crushed stone, slate, or the like, whichwill provide the film with a toothfor engagement with the concrete.

After the forms are removed from the concrete, if it be that the waterimpervious adhering to the structure carries with itfin whole "or inpart,

the coating initially applied to the forms as a basis for the formationof the film, the coating is removed as, for example, by washing it off,and

the water impervious film, if it were damaged,

for example, bythe tools used in puddling the 'concrete, is repairedwith material of the same character as 'thatused in forming the film, in

emulsion, by meansfof brushing or through the use of a spray gun'. "Thefilm may be supplemerited by a coating of any desired weight and may besupplemented'by more than one coating if desired. Under circumstanceswhere the concrete structure is .so placedas to be subjected to:

the direct action of the elements, .theinitial film may be supplementedby the application of weather resistant material, as 'for example, bythe application of bituminously impregnated fabric, for example, such asasphalt impregnated felt, the

application of which may be effected, for example, by firstcoating thefilm with a mopping of hot asphalt, or of asphalt solution, or the'like,then applying the saturated fabric in sheet form While the asphaltcoating is in an adhesive condition and finally coating the-fabric andsealing the joints, between the strips thereof with, for example, heatedasphalt or asphalt solution. It may also be desirable to embed agranularaggrer gate such as slag, crushed stone or slate in the surfaceof the supplementary coating in order that a layer of Portland cement ormagnesite stucco, or the like, may be. adhered theretofor th'e purposeof more permanently protecting thev surface of the structure and alsoforthe purposeof decoration thereof. I V v While it will be understoodthat the method embodying my, invention maybe carried out without theuse of any special apparatus, i haveillustrated in-the accompanyingdrawingthe application of the method embodyingmy inventionto theproduction of a.- concrete block, I

In the accompanying drawing: Y l ,a mould composed the reception of aFig. 1 is a sectional view of of form members ready for charge ofconcrete. V r

Fig. 2 is a sectional view of the mould shown in .Figure 1, the concretehaving beenpoured.

Fig. 3 is a perspective view, partly broken away, showing a blockproduced in the mouldof Figures 1' and 2, the form members removed fromthe block being indicated.

In the several figures :1 indicates form members, comprising in thepresent case sides and ends arranged together toform a mould for. theproduction of a block. b indicates a coating of, for example, clayslurry, applied to the interior surface of the members forming the mouldand- 0 indicates a coating of bituminous material, as asphaltappliedover the coating of clay. -slurry. d indicates a mass of concretepoured into the mould, while c indicates a coating or him of asphaltapplied over the surface of the concrete ai'ter pouring into the mould.e indicates the finished concrete block, the form members a composingthe mould having been removed. The block, it will be noted, is entirelyencased with asphalt due to adherence to it of the asphalt coating 0applied interiorly of. the mould and the asphalt coating 0' applied tothe top of the concrete after pouring into the mould. The asphaltcoating c is prevented from adhering to the interior of the mould ratherthan to the outside or the block owing to the coat of clay slurry whichis applied directly to the mould and which, as shown in Figure 3,remains on the form members on their removal from the block.

It will now be observed that as a result of my invention provision ismade for the application to concrete as it is poured into forms of awater impervious film, which coats the entire surface of the concreteand which serves to prevent evaporation of water from the concrete afterpouring and during the curing period, when the maintenance of requisitewater is essential to the sufflcient hydration of the cement content foradequate curing and, at the same time, provision is made for insuringthe retention of the film by the concrete structure after the removal ofthe forms with the result that the moisture content of the concrete willbe stabilized during the life 01' the concrete structure by the factthat the water impervious film will protect the body of the concretefrom the effect of variations in the moisture content of the atmosphereor other variable conditions which would tend to affect the moisturecontent of the concrete structure. .As has been described, the film maybe supplemented to a greater or less degree after the removal 01 thestresses and strains arising from variations in the a moisture contentthereof through change in the moisture content of contiguous bodies oratmospheric humidity.

It will be understood that I do not intend that my invention shall belimited to the precise procedure described herein by way ofillustration, nor to the use of any particular material for theformation of the water impervious film or for supplementing it, the useor any material capable of producing the results herein described beingcontemplated by me, though the method will be economically andeffectively carried out through the use of bituminous material, as forexample, asphaltum, which may be used, as has been indicated, in aheated condition, in solution in a suitable solvent, or, and which isperhaps preferable, in the form of an emulsion.

Having now fully described my invention, what I claim and desire toprotect by Letters Patent is:

A parting medium adapted for the coating or a a mold for concrete andfor the support of a flexible, water-impervious film to be adhered toconcrete formed in the mold, comprising a coating of clay formed by theapplication of an aqueous clay slurry to the mold.

a HAROLD P. HAYDEN.

